1. Field of the Invention
The present invention relates to a combustion apparatus that monitors combustion of a burner and a method for combustion control.
2. Description of the Related Art
Conventionally, a combustion apparatus is known using a flame rod which detects whether there is a flame, as a monitoring means of combustion of a burner that is a combustion means.
Concerning such monitoring of combustion, a gas water heater is known that in case a circuit detecting a spark signal of a plug or a flame detecting circuit using a flame rod is anomalous, an exhaust fan or an igniter is not brought to an operation by a safety circuit (for example, Japanese Laid-open Patent Publication No. 57-202420).
A flame detecting means of a combustion apparatus detects an ignition failure, going out during the combustion, etc. and thereby, unburnt raw gas is prevented from being emitted. If a flame rod or the like which is the flame detecting means breaks during the combustion operation although having operated normally before or at the start of the combustion operation, the condition that there is a flame may be left detected. If a burner of the combustion apparatus is misfired because a strong wind blows, supply of combustion gas stops, etc. in the above state, and the condition that there is a flame is left detected regardless of no flame. Thus, there occurs a problem such as emission of raw gas.
Concerning such a problem, there is no disclosure nor suggestion thereof in Japanese Laid-open Patent Publication No. 57-202420, and no disclosure nor suggestion about the structure, etc. for solving it is presented.